Sanding disk



Patented June 12, 1951 UNITED STATES PATENT f OFFICE SANDING DISK V Freeman S. Mitchell, San Diego, Calif. Application March 26, 1949, Serial No. 83,559

Claims.

The present invention relates to an improved air-cooled sanding disk, air-cooling being performed in a manner analogous to that shown in my prior United States Letters Patent No. 2,149,- 816, patented March 7, 1939.

An object of the present invention is to provide an improved resilient rubber pad in the form of a disk arranged as a back for a sheet of sanding paper, the pad being provided with air chan nels arranged to provide circulation of air against the underside of the paper to cool the same during the rotation of the disk about its axis.

Another object of the present invention is to provide an improved sanding disk which is efficient and reliable in performance, relatively inexpensive to manufacture, and which may be easily and quickly installed in operative position for the purposes for which the same is intended.

Another object of the present invention is to provide an improved resilient sanding disk arranged to efficiently cool the underside of a supported sanding paper, such cooling being provided by a novel arrangement of resilient ribs spaced in a novel manner to provide air-cooling ducts.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further'objects and advantages thereof, may be best understood by reference to'the following description taken in connection with the accompanying drawings in which:

Figure '1 is a view in elevation of the underside of a sanding disk embodying features of the present invention; and

Figure 2 is a view in side elevation and partly in section taken generally along the line 2-2 of Figure 1.

Referring to the drawings, the sanding disk includes a sheet metal backing plate 5 having its outer circular edge bent upwardly to provide an upturned annular flange 6. The sheet metal ring 5 has riveted thereto a hub 8. The hub 8 has a conical opening 9 contiguous to the round central opening 10 therethrough for clamping sanding paper (not shown) to such assembly, with the sanding paper adapted to contact the resilient rubber pad II which is secured to the assembly 5, 8, cementing, vulcanizing, or in other suitable manner. The outer surface of the resilient rubber pad II is provided with alternate sets of ribs [4 and channels I5 between adjacent ribs Hi. It is noted, from an inspection of Figure 1, that there are in fact four sets of ribs I4, and

such four sets have thereference numerals I8, I 9, 20 and 2| respectively. It is noted that the ribs M are arcuate in shape with channels l5 therebetween, but the ribs ll of one set curve in opposite directions from the direction in which ribs of adjacent sets are curved. For example, the ribs I 4 of set I8 may be considered to be concave ribs when referred to the direction of rotation of the disk, which is intended to rotate in the direction indicated by the arrow 22 in Figure 1 while, consistently therewith, the ribs 14 of the adjacent sets [9 and 2! may be considered to be convex ribs when referred to the same direction of movement. It is noted that the rib set I8 is spaced from the rib set 19 by a generally triangularly shaped rib 24. Similarly, the rib sets 20 and 2| are separated by a similar arcuate triangular shaped rib 25.

On the other hand, the rib sets [9, 20 are separated bya pair of generally arcuate triangularly shaped members 21, 28. Similarly, rib sets 18 and 2| are separated by a similar set of generally arcuate triangularly shaped ribs 30, 3|. It is noted that the outer ends of each of the ribs of each set terminateon a circle 32 defining the outer periphery of the disk and similarly the ribs of each set terminate on a line defining the inner circle 33.

It is noted also that the circle33 defines one edge of an annular groove 35 in the resilient pad I I, as indicated in both Figures 1 and 2. In other words, each one of the channels [5 extends inwardly and is in communication with the annular groove 35 in the pad II. The hub 8 is adapted to be supported on the output shaft of the motor and is purposely made hollow, for that purpose to receive a screw or bolt with a fiat head or conical head seated in the conical opening 9 with sanding paper clamped between such bolt head and the wall defining the conical or flared opening 9 of the hub 8. When the sanding paper is thus clamped by a flat head type of machine screw or bolt recessed in the conical opening 9, the head of the bolt is below (Figure 2) the top edge of the sanding disk proper so that such bolt head does not contact the work although it does clamp the sanding paper which is resiliently pressed against the work by the resilient rubber ribs 14..

The particular shape of the ribs 14 and their disposition in sets I8, I9, 29 and 2| so as to be curved in opposite directions in alternate sets is not merely a matter of design but is intended and serves to promote an efficient flow of cooling air past the underside of the sanding paper (not shown) with relative quietness. For example, as the sanding disk rotates in the direction indicated by the arrow 22, cooling air for the sanding paper tends to flow, for example, in the directions indicated by the arrowed line 34 which extends inwardly into the channels defined by concave shaped ribs into the inner annular groove 35 and then outwardly through channels defined by convex type of ribs in an adjacent set.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. A sanding disk pad adapted to support sanding paper on spaced resilient generally radially extending ribs defining air channels therebetween for cooling the underside of said sanding paper, said ribs'being disposed in spaced sets, one of said sets defining a corresponding set of generally radial and concave air channels, and the other one of said sets defining a corresponding set of generally radial and convex air channels, the inner ends of said concave and convex air channels being in communication with each other and the outer ends of said concave and convex air channels being vented to the atmosphere to promote the flow of cooling air inwardly and outwardly' with respect to the rotational axis of said disk.

2'. A resilient sanding disk pad adapted to support'sanding paper and to cause the same to contact a workpiece, said sanding disk comprising a plurality of spaced concave and convex shaped ribs for contacting the underside of said sanding paper and defining therebetween sets of concave and convex air channels extending generally radially, the inner ends of said concave and convex air channels being in communication with one another and the outer ends of said concave and convex channels being in communication with the atmosphere to promote the flow of cooling air inwardly and outwardly with respect to the rotational axis of the disk pad.

3. A resilient sanding. disk' padhaving mounted thereon a hub member with a tapered apertured portion to receive a tapered pin for clamping the central portion of sanding paper thereon with the sanding paper overlying said disk pad, said disk pad having an inner annular air-cooling groove in communication with the underside of the sanding paper overlying the same, said disk pad having a plurality of radially extending arcuate shaped spaced ribs defining therebetween air channels in communication with said inner annular groove, said annular air cooling groove being concentrically disposed and spaced radially outwardly from said tapered apertured portion, and: the outer ends of said air channels defined by said arcuate shaped spaced ribs being vented to the atmosphere.

4. A resilient sanding disk pad comprising a plurality of arcuate shaped spaced resilient sanding paper supporting ribs defining therebetween alternate concave and convex air channels, said concave and convex air channels extending generally radially With their inner ends in communication W-itheach other and with their outer ends vented to the atmosphere to promote the free flow of cooling air radially inwardly and then radially outwardly with respect to the rotational axisoi the disk pad.

5. A resilient sanding disk pad comprising a resilient disk with an inner annular groove, said disk having formed thereon a plurality of generally radially spaced concave and convex sets of sanding paper engaging ribs defining therebetween corresponding concave and convex sets of cooling air channels extending generally radially with their inner ends in communication with said inner annular groove and with the outer ends of said air channels vented to the atmosphere to promote'the free flow of cooling air inwardly'and outwardly with respect to the rotational axis of said disk.

S; MITCHELL.

REFERENCES CITED The following references are of record in the file of'this patent:

UNITED STATES PATENTS Number Name Date 472,823 Ross Apr. 12, 1892 1,355,345 Lorenz Oct. 12, 1920 2,334,642 Moore Nov. 16, 1943 

